Solid-state image pickup device, electronic apparatus using such solid-state image pickup device and method of manufacturing solid-state image pickup device

Abstract

A back-illuminated type solid-state image pickup device ( 1041 ) includes read circuits (Tr 1 , Tr 2 ) formed on one surface of a semiconductor substrate ( 1042 ) to read a signal from a photo-electric conversion element (PD) formed on the semiconductor substrate ( 1042 ), in which electric charges (e) generated in a photo-electric conversion region ( 1052 c 1 ) formed under at least one portion of the read circuits (Tr 1 , Tr 2 ) are collected to an electric charge accumulation region ( 1052 a ) formed on one surface side of the semiconductor substrate ( 1042 ) of the photo-electric conversion element (PD) by electric field formed within the photo-electric conversion element (PD). Thus, the solid-state image pickup device and the camera are able to make the size of pixel become very small without lowering a saturation electric charge amount (Qs) and sensitivity.

1. A solid-state image pickup device comprising:
 a first semiconductor region ( 1052   b ) of a first conductivity type between an electric charge accumulation region ( 1052   a ) of the first conductivity type and a second semiconductor region ( 1052   c ) of the first conductivity type; 
 a third semiconductor region ( 1052   c   1 ) of the first conductivity type between a semiconductor well region ( 1046 ) of a second conductivity type and said second semiconductor region ( 1052   c ), 
 wherein an impurity concentration of the first conductivity type for said electric charge accumulation region ( 1052   a ) is higher than an impurity concentration of the first conductivity type for said third semiconductor region ( 1052   c   1 ), 
 wherein an impurity concentration of the first conductivity type for said first semiconductor region ( 1052   b ) is higher than an impurity concentration of the first conductivity type for said electric charge accumulation region ( 1052   a ). 
 
     
     
       2. A solid-state image pickup device according to  claim 1 , wherein the conductivity of the first conductivity type is opposite to the conductivity of the second conductivity type. 
     
     
       3. A solid-state image pickup device according to  claim 1 , wherein said first semiconductor region ( 1052   b ), said third semiconductor region ( 1052   c   1 ) and said second semiconductor region ( 1052   c ) are bordered by pixel separation regions ( 1043 ) of the second conductivity type. 
     
     
       4. A solid-state image pickup device according to  claim 3 , wherein an impurity concentration of the second conductivity type for said pixel separation regions ( 1043 ) decreases from a back surface side of a substrate to a substrate surface side of the substrate. 
     
     
       5. A solid-state image pickup device comprising:
 a first semiconductor region ( 1052   b ) of a first conductivity type between an electric charge accumulation region ( 1052   a ) of the first conductivity type and a second semiconductor region ( 1052   c ) of the first conductivity type; 
 a third semiconductor region ( 1052   c   1 ) of the first conductivity type between a semiconductor well region ( 1046 ) of a second conductivity type and said second semiconductor region ( 1052   c ), 
 wherein an impurity concentration of the first conductivity type for said electric charge accumulation region ( 1052   a ) is higher than an impurity concentration of the first conductivity type for said third semiconductor region ( 1052   c   1 ), 
 wherein a channel region ( 1055 ) is between an accumulation layer ( 1053 ) of the second conductivity type and said semiconductor well region ( 1046 ), an impurity concentration of the accumulation layer ( 1053 ) decreasing toward said channel region ( 1055 ). 
 
     
     
       6. A solid-state image pickup device comprising:
 a first semiconductor region ( 1052   b ) of a first conductivity type between an electric charge accumulation region ( 1052   a ) of the first conductivity type and a second semiconductor region ( 1052   c ) of the first conductivity type; 
 a third semiconductor region ( 1052   c   1 ) of the first conductivity type between a semiconductor well region ( 1046 ) of a second conductivity type and said second semiconductor region ( 1052   c ), 
 wherein an impurity concentration of the first conductivity type for said electric charge accumulation region ( 1052   a ) is higher than an impurity concentration of the first conductivity type for said third semiconductor region ( 1052   c   1 ), 
 wherein a channel region ( 1055 ) is between an accumulation layer ( 1053 ) of the second conductivity type and said semiconductor well region ( 1046 ), 
 wherein an impurity concentration of the second conductivity type for the accumulation layer ( 1053 ) decreases toward said channel region ( 1055 ). 
 
     
     
       7. A solid-state image pickup device according to  claim 5 , wherein said electric charge accumulation region ( 1052   a ) is between said accumulation layer ( 1053 ) and said first semiconductor region ( 1052   b ). 
     
     
       8. A solid-state image pickup device according to  claim 5 , wherein said channel region ( 1055 ) is between a source/drain region ( 1047 ,  1049 ) of the first conductivity type and said electric charge accumulation region ( 1052   a ), said source/drain region ( 1047 ,  1049 ) being within said semiconductor well region ( 1046 ). 
     
     
       9. A solid-state image pickup device according to  claim 5 , wherein said channel region ( 1055 ) is between a region portion ( 1056 ) of the first conductivity type and a gate electrode ( 1048 ). 
     
     
       10. A solid-state image pickup device according to  claim 9 , wherein said region portion ( 1056 ) is between said electric charge accumulation region ( 1052   a ) and said semiconductor well region ( 1046 ). 
     
     
       11. A solid-state image pickup device according to  claim 9 , wherein said region portion ( 1056 ) is between said channel region ( 1055 ) and said first semiconductor region ( 1052   b ). 
     
     
       12. A solid-state image pickup device according to  claim 5 , wherein said second semiconductor region ( 1052   c ) is between an accumulation layer ( 1054 ) of the second conductivity type and said accumulation layer ( 1053 ). 
     
     
       13. A solid-state image pickup device according to  claim 5 , wherein incident light upon said accumulation layer ( 1054 ) is convertible into a signal. 
     
     
       14. A camera including the solid-state image pickup device of  claim 1 . 
     
     
       15. A method of manufacturing the solid-state image pickup device of  claim 1 , the method comprising the steps of:
 forming the second semiconductor region ( 1052   c ); 
 forming the first semiconductor region ( 1052   b ) and the third semiconductor region ( 1052   c   1 ); 
 forming the electric charge accumulation region ( 1052   a ); and 
 forming the semiconductor well region ( 1046 ). 
 
     
     
       16. A method of manufacturing a camera comprising the method according to  claim 15 .